Re: [PATCH 2/2] PCI: sophgo-dwc: Add Sophgo SG2044 PCIe driver

[Bjorn Helgaas]

On Tue, Mar 04, 2025 at 03:12:38PM +0800, Inochi Amaoto wrote:
> Add support for DesignWare-based PCIe controller in SG2044 SoC.

> +static void sophgo_intx_irq_eoi(struct irq_data *d)
> +{
> +}

The empty .irq_eoi() is unusual.  Why do you need it?

I see that the existence of chip->irq_eoi() makes a difference in
chained_irq_enter() and chained_irq_exit(), but I'm surprised that
this is the only driver in drivers/pci/controller/ that implements an
empty .irq_eoi().

A comment here about what is special would be helpful.

> +static struct irq_chip sophgo_intx_irq_chip = {
> +	.name			= "INTx",
> +	.irq_mask		= sophgo_intx_irq_mask,
> +	.irq_unmask		= sophgo_intx_irq_unmask,
> +	.irq_eoi		= sophgo_intx_irq_eoi,
> +};